I'm working on a 4WD skid steer robot which uses ros control and the diff drive controller.
If I set my wheel radius multiplier to 1.0, the robot seems to go extremely slow (doesn't seem to be moving at the speed I tell it to) and the odometry data seems off. When checking the odometry topic published by the diff drive controller, if I move the robot forward 60cm (checked with a ruler), the controller thinks the robot has moved over 2m...
If I change my radius multiplier to 0.195 the position data of the odometry seems more accurate, reflecting my real life measurements. With this multiplier however, when I go at very high speed and look at the odom TF in Rviz the robot starts going backwards suddenly (in Rviz and in the odom topic as well but the actual robot is moving forward). This doesn't happen when the multiplier is set to 1.0 though.
What could possibly be happening? I understand that I have to play with the wheel separation multiplier because of the skid steer nature of the robot vs differential style, but the radius multiplier should stay at 1? I have checked my urdf and hardware interface and don't think they're the issue but anything I should look for?
Here's my diff drive config file:
robot_joint_publisher:
type: "joint_state_controller/JointStateController"
publish_rate: 100
robot_velocity_controller:
type: "diff_drive_controller/DiffDriveController"
left_wheel: ['front_left_wheel', 'rear_left_wheel']
right_wheel: ['front_right_wheel', 'rear_right_wheel']
publish_rate: 100
pose_covariance_diagonal: [0.001, 0.001, 0.001, 0.001, 0.001, 0.03] #Need to define?
twist_covariance_diagonal: [0.001, 0.001, 0.001, 0.001, 0.001, 0.03] #Need to define?
cmd_vel_timeout: 0.25
velocity_rolling_window_size: 2
wheel_separation : 0.42 #Distance between left and right
wheel_radius : 0.1651
# Base frame_id
base_frame_id: base_link
# Odometry fused with IMU is published by robot_localization, so
# no need to publish a TF based on encoders alone.
enable_odom_tf: true
# Navvy hardware provides wheel velocities
estimate_velocity_from_position: false
# Wheel separation and radius multipliers
wheel_separation_multiplier: 2.0 # husky 1.875 - Will need to adjust based on odom readings
wheel_radius_multiplier : 0.195 # default: 1.0
# Velocity and acceleration limits - To define
# Whenever a min_* is unspecified, default to -max_*
linear:
x:
has_velocity_limits : true
max_velocity : 3.0 # m/s
has_acceleration_limits: true
max_acceleration : 3.0 # m/s^2
angular:
z:
has_velocity_limits : true
max_velocity : 9.0 # rad/s
has_acceleration_limits: true
max_acceleration : 6.0 # rad/s^2
I'm working on a 4WD skid steer robot which uses ros control and the diff drive controller.
If I set my wheel radius multiplier to 1.0, the robot seems to go extremely slow (doesn't seem to be moving at the speed I tell it to) and the odometry data seems off. When checking the odometry topic published by the diff drive controller, if I move the robot forward 60cm (checked with a ruler), the controller thinks the robot has moved over 2m...
If I change my radius multiplier to 0.195 the position data of the odometry seems more accurate, reflecting my real life measurements. With this multiplier however, when I go at very high speed and look at the odom TF in Rviz the robot starts going backwards suddenly (in Rviz and in the odom topic as well but the actual robot is moving forward). This doesn't happen when the multiplier is set to 1.0 though.
What could possibly be happening? I understand that I have to play with the wheel separation multiplier because of the skid steer nature of the robot vs differential style, but the radius multiplier should stay at 1? I have checked my urdf and hardware interface and don't think they're the issue but anything I should look for?
Here's my diff drive config file: